The invention proceeds from a submersible motor unit for a centrifugal pump.
A typical pump of the past is described in DE-C-38 20 003. It comprises a common housing which consists of a one-piece tubular jacket part with a floor part fastened thereto, of an electrical drive motor for the centrifugal pump and of an electrical control means for setting the rotary speed and/or the torque of the drive motor wherein the drive motor and the control means are arranged behind one another in the common housing. An insulated connection cable which is introduced on the end of the motor on the pump side and runs within the common housing supplies the control means with electrical energy. The electrical control means consists of a power component which produces considerable heat and which is fastened to an intermediately connected transverse wall in the common housing in order to be cooled by the cooling flow in the rotor space of the drive motor, and of an electrical element spacially separated from the power component, e.g. a capacitor which is fastened to the floor part of the common housing and may be surrounded by a pressure resistant mass.
In DE-C-36 42 727 there is described a further submersible motor unit. This unit comprises an assembled housing which consists of a first tubular jacket part in which there is located the electrical drive motor for the centrifugal pump and of a second jacket part unreleasably fastened thereto, with an end floor, in which there is located the electrical control means for the drive motor. The electrical control means, e.g. a frequency converter is electrically connected to the drive motor via a plug connection design in order to control the drive motor. The current supply of the electrical control means is effected by the drive motor. The control means whose possible spacial arrangement is shown in FIG. 1 of this document contains in its housing the usual electronics which is encapsulated in a pressure tight manner in this housing by way of rigid materials.
A considerable disadvantage of these prior known submersible motor units lies in the fact that a disposal of non-usable submersible motor units or parts thereof, with due respect to the materials, may not be carried out in an economical manner. A large expense with respect to labor and time is required for this since the disaggregation of the units is very complicated and thus causes high costs. To a relatively limited extent there is only a rough disaggregation which must be carried out with numerous separating tools, but also often no disaggregation of the units takes place. The occuring coarse parts or complete units are instead reduced in size to the required degree in a shredder installation. The reduced mass is only partly reused and the rest are laid aside in a dump. Here environmental damage may occur since the electronic components and the solid matter surrounding these and casting masses contain components which with the earth or other matter may cause environmentally damaging compounds.
On account of the cost, legal rules for the environmentally friendly disposal are often ignored.
The described state of the art further from the point of view of preventing environmentally damaging refuse only permits an economical repair of the submersible motor units in a limited manner. Often for a repair of the inner parts of the units the common housing for the motor and the control means must be damaged to a great extent and mostly damaged beyond repair so that there arises additional costs on account of a new common housing. Apart from this also the control means for the motor essentially cannot be repaired economically since its electronic components for reasons of stability, for the housing of its own, which itself must be unrepairably damaged, are surrounded by solid matter and/or casting masses.
Furthermore the cooling of the electrical control means for the motor is also not satisfactory since the heat occuring from the electrical control means and in particular from its components strongly producing heat may only be removed at a high excess temperature.